During the morning’s confusion, Rosecrans tried to shuffle troops across the battlefield to the areas he thought needed them most. As a result, he ordered the division of Brig. Gen. Thomas Woods to fill a hole in his line that didn’t exist. In doing so, he inadvertently created a hole instead–at exactly the place and time that Lt. Gen. James Longstreet sent his entire wing of the Confederate army forward for a massive attack.

Shortly after 11:00 a.m., Confederates swept across the Brotherton Farm and into Dyer Field, catching the Federals off guard. “[I]t was impossible for my troops to hold their position,” one Federal officer said. “The line melted away . . . .”

The event that became known as “the Breakthrough” was actually much worse. As Longstreet’s wing of the army moved forward, not only did it punch through the yawning gap left by Wood’s departure, it also rolled over one Federal division (Jefferson C. Davis’s) before smashing into and routing another (Sheridan’s). The whole right wing of the Union army collapsed in a short time.

(Above:) The Wilder monument, rising 85 feet above the battlefield, is the tallest monument at Chickamauga. It stands amidst a cluster of other monuments, attesting to the severity of the fighting in the area around the Glenn Farm, as Federals desperately tried to prevent a total rout.